Process of producing colored-photographic prints



May 15, 1928. 1,669,869

E. H. FARMER PROCESS OF PRODUCING COLORED PHOTOGRAPHIC PRINTS FiledApril 26, 1927 gvweutoz Patented May 15, 1928.

ERNEST HOWARD PARKER, 01, LONDON, ENGLAND.

PROCESS OF PRODUCIFG COLORED-iHOTOG-RAPHIC PRINTS.

flpplication filed April 26, 1927. Serial No. 188,648.

My invention consists in the novel features hereinafter described,reference being had to the accompanying drawing, which illustrates,schematically, the -manner in 5 which my invention is carried intoeifect, and said invention is fully disclosed in the followingdescription and claims.

The object of my invention is to provide a simple and practical processfor the produc- 1 tion of colored hoto raphic prints, capable of beingcarried out by anyone of ordinary intelligence, and without artistictraining, in which the pigments, in association with a suitable vehicle,are roughly appliedto a surface bearing a photographic image, thepigments being rendered permanent under the control of the photographicimage, and in proportion to the density thereof, prefer ably by theapplication of material which will react upon the vehicle in thepresence of'a photographic image, and in accordance with the densitythereof, to harden the vehicle and fix the colors, the excess of vehicleand pigments being dissolved off and re- 2 moved from the print, and thedegree to which the photographic under-print is visible being capable ofvariation by bleaching to a. greater or less extent, if desired. Inother words, the colors, in association with so a suitable vehicle,which is,preferably of a gelatinous character, are applied to differentportions of the print under the control of the operator, and thephotographic image appropriates, in various parts. thereof, and

36 makes permanent thereof, portions vof the pigments in accordance withthe variations of density of the photographic image, with the resultthat the photographic image controls not only the outlines of thecolors, but

40 the delicate gradations and shadings thereof,

in accordance with the variations of density,

and with the result that the prints'resemble fine water colorpaintings,to a greater or less extent, depending somewhat upon the degree in whichthe photographic image itself is obscured by the colors or bleached outby a subsequent bleaching process, if this is desired.

In the drawing, in which I have attempted to show, schematically, ordiagrammatically,

the operation of my process, and the print produced thereby,

Fig. 1 is a sectional view, greatly exaggerated, representing aphotographic image,

upon a suitable supporting medium, as

paper, and showing the pigments and vehicle for the image, a materialsuitable for brush work, as, for example, drawing paper, as

this not only facilitates the application of:

the pigments, but such paper has a rough surface which in itseli givescharacter and quality to the finished print. Such a paper or othersurface may be conveniently sensitized with a thin coating of gelatine(a very small quantity of gelatine being employed), with bromide orchloride of silver, for example, which is printed in the usual mannerunder a negative, the exposure being preferably timed to produce a weakprint which is then developed in any I usual or preferred manner as, forexample, by the use of metolhydrokinone developer, or any other suitabledeveloper. The surface of the print after development, will contain inthe darker portions, metallic silver in a finely divided cony Fig. 2 isa similar View showing the result.

dition, and in different densities, according to the character of thephotographic image. In the preparation of the sensitized surface orpaper, care should be taken to avoid the use of oxidizing agents, or anymaterial likely to combine with or effect the reducing power ofthesilver set free by the developer.

After the prlnt is prepared, and preferably while it is still damp, Iapply or paint onto its surface, with water color pigments, mixed with agelatinous vehicle, preferably an aqueous solution containing a smallpercentage of glue or gelatine and charging each portion of the printwith an excess of the pigment and vehicle. A convenient method ofpreparing the painting colors, is to take a four per cent solution ofgelatine which has been rendered partially insoluble, by the addition of.a few drops of a four per cent ployed for the purpose.

It will be understood that the operator can select the colors to be usedon different portions of the print, and that different portions of theprint are painted over with different colors. The painting, however,does not require expert training, as the-pigmented vehicle may be puton' roughly over the different portions of the print, and may evenoverlap at their marginal portions, without injury to the print. 'Iprefer to keep the print in a condition sufficiently warm to maintainthe pigmented vehicle a fluid, while it is painted on, and when it isdesired to avoid getting any color on any particular area of the print,such area or areas, may be painted over with the plain gelatine solutionor vehicle, without color, after which the colors from the adjacentcolored portions may overlap the plain gelatine coated portions withoutdanger of. coloring the same. "WVhile I prefer to paint the printsimmediately after development and a suflicient washing to remove thedeveloper and 'before fixing, it is to be understood that the pigmentedvehicle may be applied after the fixing of the prints, and a few minutesWashing to remove thefixing solution (hyposulphite of soda), and furtherthat, should it be desired to keep or store the prints before they arepainted, this'may also be done, but in such case the developedprints-.must be fixed and dried for storage, and later bleached with aweak solution of ferricyanide of potash and bromide of potash, andre-developed before the pigmented vehicle is applied.

After the prints are painted with the pigmented vehicle, which. isconveniently applied by a brush or brushes,,the print is treated withwhat I term a tanning agent,

' or solution, to develop the color, or in other words, to enable thephotographic image to select portions of the applied colors, inaccordance with the masses of the photographic image, and in proportionto. the variations in density of the image. For this purpose I prefer toemploy a solution which will re-act in the presence of the silver image,so as to set'free a substance which tans or hardens the gelatine vehiclewhere the deposited silver of the image is present, and

in proportion to itsdensity upon the paper or other supporting surface.A suitable solution which I have employed for this purpose is thefollowing Potassium bromide Potassium lnchromate; Potassiumferricyanide' 1,0 grain 0.5 grain 0.25 grain Acetic acid (glacial) I. 10minims Alcohol (methylated) 3ounces Water 5 ounces and apply untoitself, portions of the excess pigmented vehicle which has been appliedto it exactly in accordance with the outline and density of the silverdeposit. The quantity of all the eolors is determined by the periodduring which reaction of the tanning agent or solution is permitted toact, the

relative degrees and shadings of the several colors being determined bythe varying densities of the variations of the silver depositedconstituting the photographic image.

In some instances, instead of fixing the color by immersing the printsin a bath of the solution above described, a few drops of a strongersolution of the same materials may be added to the gelatine vehicle andpigments carried thereby before they are painted onto the print, but Iprefer to pro- .ceed as before stated.

When the color has been developed to the desired degree of intensity,the remaining por tions of the pigmented gelatine not selected andhardened by the reaction with the silver deposit upon the paper, andforming the photographic image, is dissolved off and removed. This maybe accomplished by washing the developed colored print in warm water,leaving only the photographic image ill) and the hardened portions ofthe pigmented gelatine on the supporting surface. 4

The print is then finally fixed by im mersing it in a ten percentsolution of hyposulphite of soda.

In developing the colors, the silver underprint may remain, or if it isdesired, the silver under-print may be bleached, especially in thedelicate or lighter tones, or bleached and removed altogether, asdesired, leaving only the colors upon the surface. This bleaching actionmay be effected by the ordinary means, as ferricyanide of potassium andbromide of potassium, and the degree of bleaching may be regulated bythe length of time the print remains immersed in the bath and thestrength of the bleaching bath.

y desired, the bleaching action may take place after the colored printhas-been washed to remove the soluble pigmented vehicle,

transfer film is a feature,

in which case the bleaching action will be fully visible, andmay becarried to the exact extent desired; It will also be understood thatthecolor developing or tanning agent or solution maybe varied somewhatto suitdifferent-ly prepared papers.

In carrying out my invention, the use of insoluble-surface paperswhich'are necescarry. in processes in which the adhesion of is .notnecessary, and such papers willnotv ordinarily be employed. ()n thecontrary, all of the natural surface papers em loyed for drawing andpainting are availa' 1e and will retain their natural surfaces andcontribute to the pleasing eflf'ect of the colored prints which ineffeet are similar to fine oifset prints. By painting different parts ofthe prints with the pigmented gelatinous yehicle, containing differentquantities of .the same color of pigment, the vehicle containing largerproportions of the pigment, being painted over the dark portions of theprint, and the vehicle containing lesser quantities of the pigment beingpainted over the lighter or weaker portions of the print, the finishedprints will reproduce the full range of gradation of colors, includingthe most delicate and lightest tints of the same.

In the accompanying drawing 1 have en-. deavored to illustrate,schematically or dia-. grammatidally, the operation of my improvedprocess in the production of my im- .proved colored prints. In Fig. l,for exampie, 1, represents the image support or paper, preferably havinga roughened surface, indicated at 2, which is sensitized, exposed tolight, and developed, as before described, the portions of the silverimage of different densities being indicated at 3. 4, 5, 6, 7, 8, 9 and10, represent portions of the vehicle igmented with diflerent colors asselected iy' the operator in any desired number and any desired range ofshades of diiferent color, such portions of the drawing, Fig. 1, beingin this instance shaded so as to represent red, green, orange, blue,brown, yellow, and black, butof course the particular colors and shadesof particular colors will vary with each image, in accordance with itscharacteristics. The proportions of the several partsillustrated in thedrawing and necessarily greatly exaggerated in an endeavor to convey theidea graphically, and it will be understood that the pigmented vehicleis applied in excess of the requirements of the photographic image, asbefore set forth. The dotted line in Fig. 1 represents, schematically,the portions of the several and diiierently colored pigmented vehicleswhich are hardened by the so-called tanning agent, as previouslydescribed, Fig. 1, representing the pigmented '7, 8, 9 and 10 printbefore the excess of pigmented vehicle is dissolved,ofi of the print;

In Fig. 2 I have represented the image sup rt, or paper, 1', having itsroughened sur ace, 2, carrying the photographic image, and depositedsilver, represented at 3, and showing the'adhering hardened portions ofthe pigmented vehicle in the different colors shown inlig. 1, from whichthe surplus unhardened pigmented vehicle has been separated b washingand dissolving it, in the manner escribed, leaving the finished prints1n colors, which hardened portions of the vehicle are presented at 4, 56', and correspond with the dotted lines shown in Fig. 1.

In the foregoin r specification, and in the following claims lfiiaveused the term gelatinous as meaning a substance which contains gelatine,or analogous material, having the chemical characteristics of gelatine.7

What I claim and desire to secure by Letters Patent is z- I. 'The hereindescribed process of producing photographic colored prints, which printupon gelatinous vehicle and fix ing photographic colored prints, whichconsists in preparing a-photographic underprint' upon a suitablesupport, consisting of a deposit of silver in finely divided conditionand varying in density in difi'erent portions thereof, applyingdifierent colors to a gelatinous vehicle, to difierent portions of thesurface of the photographic image, treating the pigmented vehicle with amaterial capable of reacting upon the silver of the image to produce atanning agent, and hardening the vehicle containing the colors, inproportion to the density or the silver deposit of the image, anddissolving off the unhardened portions of the vehicle and pigmentscarried thereby.

3. The herein described process of producing photographic coloredprints, which consists in preparing a photographic image in differentdegrees of density at difierent portions thereof upon a suitablesupporting surface, applying difi'erent colored pig ments to diiierentportions of the photographic image, in association with a vehicle,elfecting the hardening of the vehicle in proportion to the variationsof density of the on I ing photographic colored prints, which consistsin preparing a photographic image in deposited silver upon a suitablesurface, applying difi'erent colored pigments to difier ent portions ofthe photographic image in association with a'gelatinous Vehicle, andsubjecting the pigmented vehicle to the action of a tanning materialcontaining chromic salt, adapted to react in the presence of the silverof the image, to set free a chrome tanning agent and harden thegelatinous vehicle, in proportion to the variations in density of thephotographic image, to fix pigments thereon, and dissolving ofi theunhardened excess vehicle and pigments.

5. The herein described process of producing photographic coloredprints, which consists in preparing a photographic image in depositedsilver "upon a suitable surface, applying different colored pigments toditi'erent portions of the photographic im-- age in association With agelatinous vehicle, treating the print with a solution containingpotassium bromide, potassium bichromate, potassium ferricyanide, andacetic acid, to set free in reaction with the silver of the image, achrome tanning agent and harden portions of the pigmented vehicle uponthe silver image, iii proportion to the variation of density thereof, tofix the pigments, dissolving otf the excess unhardened vehicle andpigments, and fixing the print with hyposulphite of soda.

6. The herein described photographic colmed print, comprising asupporting surface and a vehicle carrying pigments of different colors,and hardened upon a photographic image and said support in accordancewith the details and variations in density thereof.

7. Theherein described photographic colored print, comprising asupporting surface, a photographic image thereon, and a gelatinousvehicle carrying different pigments of difierent color applied todifferent portions of the photographic image, and hardened thereon inaccordance with the details of and variations in density of thephotographic image. 4

\ 8. The herein described photographic colored print, comprising asupporting surface, a photographic image in. deposited silver thereon, agelatinous vehicle carrying pigments ot'difi'erent colors'applied todifferent portions of thephotographic image and hardened thereon, inaccordance with the details of said image, and in proportion to thevariations in the density thereof.

In testimony-whereof I afiix my signature ERNEST HQWARD FARMER.

